Engineering Commons^™

Solid Loading Effects On The Assembly Of Alumina Particles In Aqueous Suspensions Due To The Dielectrophoretic Forces, Sivakumar Chithamallu, Rohan Kiran Parai, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

Current work in situ investigated the mechanisms of the interparticle interactions that evolve in dilute aqueous alumina suspensions subjected to alternating current (AC) electric field and the effects of solid loading of suspensions. The interactions were investigated for alumina suspension compositions in the 0.005‒0.04 vol.% solid loading range. Field‐induced interactions evolved via particle motion and dynamic assembly, chain formation parallel to the direction of the applied field and chain growth, chain cross‐linking, and chain thickening. The evolution time of each of those events was rapidly accelerated with solid loading. While chain cross‐linking was negligible in low solid loading suspensions, a …

Sustainable Enzymatic Extraction Of High-Purity Chitin From Button Mushroom (Agaricus Bisporus) Off-Production Waste: Influence Of Alkaline Pre-Treatment On Physicochemical Properties, Buliyaminu A. Alimi, Shivani Pathania, Jude Wilson, Brendan Duffy, Jesus Maria Frias

Articles

This study investigated chitin extraction from the stalks and atypical mushrooms, the often-produced waste in the mushroom production process, using a simultaneous application of protease and glucanase with or without an alkaline pretreatment stage. A commercial chitin, chemically extracted from A. bisporus was used as the control. The purity of extracted chitin (98.92–99.36 %) was slightly lower than commercial chitin (99.80 %), but with comparable physicochemical properties (p < 0.05). All enzymatically extracted chitin in this study exhibited an agglomerated, microfibrillar and irregular structure, while the control showed standalone granules with weathering and cracks on the surfaces. The XRD and FTIR spectra indicated that the extracted chitin and the control belong to the α-allotrope group. The degree of acetylation was higher in the extracted chitin (76.97–78.22 %) than in the control (75.05 %). The highest molecular weight obtained for the extracted chitin was 4.53 × 102 KDa (W0548). The study demonstrated the possibility of producing pure, high molecular weight chitin from the waste produced during the commercial production of button mushrooms, using a potentially more sustainable approach than the traditional one. This enzymatic approach reduces chemical waste, as shown by the excellent results obtained for samples without the pre-treatment stage, and improves environmental safety compared to traditional methods.

Nebraska Test #2301: Claas Xerion 12.650, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Test #2300: Claas Xerion 12.590 Terra Trac, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Test #2297: John Deere 9rx 770, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Test #2298: John Deere 9rx 830, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary #1291: Fendt 614 Vario, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Characterization And Leaching Feasibility Studies Of Copper Flue Dust For The Recovery Of Main And Trace Metals, Fardis Nakhaei, Marek Locmelis, Lana Alagha, Michael S. Moats, Carlos Eyzaguirre, Cory Smith

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Although copper smelter dust (CSD) is classified as hazardous waste, it also serves as a valuable secondary resource, offering potential for the recovery of critical elements. In this study, CSD samples were collected from the waste heat boiler (WHB) and electrostatic precipitator (ESP) units connected to the flash smelting furnace at a copper smelter. The representative samples were extensively characterized by particle size, and chemical and mineralogical analyses. Following sample characterization, leaching experiments were performed to evaluate the potential extraction of Cu, Fe, As, Zn, Pb, In, Ga, and Ge from the flue dusts. Distilled water, H2SO4, and HCl were …

Designing Robust Quasi-2d Perovskites Thin Films For Stable Light-Emitting Applications, Sharmistha Khan, Reshna Shrestha, Mengru Jin, Doyun Kim, Guan Lin Chen, Ruipeng Li, Yijia Gu, Qing Tu, Namyoung Ahn, Wanyi Nie

Materials Science and Engineering Faculty Research & Creative Works

Quasi-2D perovskite made with organic spacers co-crystallized with inorganic cesium lead bromide inorganics is demonstrated for near unity photoluminescence quantum yield at room temperature. However, light emitting diodes made with quasi-2D perovskites rapidly degrade which remains a major bottleneck in this field. In this work, It is shown that the bright emission originates from finely tuned multi-component 2D nano-crystalline phases that are thermodynamically unstable. The bright emission is extremely sensitive to external stimuli and the emission quickly dims away upon heating. After a detailed analysis of their optical and morphological properties, the degradation is attributed to 2D phase redistribution associated …

Quality Improvement Of Polycarbonate Medical Device By Moldex3d And Taguchi Doe, Upoma Saha, Wael Mokhtar

Open Access Publishing Support Funded Articles

Incorporating a new design combined with a thermoplastic material without having a prior process database may cause numerous defects in the molded part. Along with the initial setup cost, the scrape due to defects can add additional costs to the production. To address such issues, the numerical analysis tool Moldex3D was used to conduct simulations, and Taguchi Design of Experiment (DOE) was performed to optimize the process parameters. For this study, a classic medical device like the safety goggle model has been chosen as a subject. An amorphous material, polycarbonate, was used because of its transparent and significant thermal properties. …

Improving Torque Distribution Of The Baja Car's Drive Shaft, Natalie E. Falerios

Senior Honors Theses and Projects

This honors thesis analyzes torque variation in the drive shaft system of the Baja SAE vehicle, with a focus on the effects of universal joint (U-joint) geometry and phasing in an inherited and new drive shaft design. The original drivetrain was inherited from a previous team and affected the seat placement that did not comply with the Baja SAE rules. This resulted in a redesign of the drive shaft and evaluation of both the inherited and redesigned configurations’ performance. An initial experiment was created and attempted to analyze the torque variation in the drive shaft, however, there were time constraints …

Exploration And Synthesis Of Tin Intermetallic Single Crystals, Jared L. Shortt

Graduate Theses/Dissertations

This thesis presents the synthesis and characterization of two tin-based intermetallic compounds: Mn₄.₁₂Sn and Ni₆Sn₈Ge₀.₄₇. Single crystals were grown using a high-temperature self-flux method, allowing for the formation of phase-pure samples suitable for structural and physical property analysis. The crystalline phases were identified and refined using powder and single-crystal X-ray diffraction (XRD), while scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM/EDS) was employed to verify stoichiometry and homogeneity. Magnetization measurements performed using a superconducting quantum interference device (SQUID) magnetometer revealed distinct magnetic behavior in the manganese-rich compound, while the nickel-based compound was explored for potential magnetic features arising from …

The Structure, Properties And Dissolution Behaviors Of Phosphate Glasses, Han Zhang

Doctoral Dissertations

The poor chemical durability remains a critical challenge for the application of phosphate glasses. This study investigates the compositional influences on the structure, properties and chemical durability of Li2O-ZnO-P₂O₅ glasses. Their structural characteristics were analyzed utilizing high-performance liquid chromatography, Raman spectroscopy, and X-ray photoelectron spectroscopy. The incorporation of (Li2O+ZnO) in LZeq glasses depolymerizes the phosphate network. In LZ40P and LZ45P glasses, Li⁺ initially replaces Zn²⁺ associated with non-bridging oxygens (NBOs) in Q² tetrahedra. Once the substitution in Q² is complete, further Li⁺ incorporation leads to the replacement of Zn²⁺ in Q^{1 …}

Computation Of Natural Relative Trajectories In The Elliptic Restricted Three-Body Problem, Dane Huck

Masters Theses

"Humankind’s presence in deep space is certain to increase throughout future decades. Future missions will continue to exploit the complex dynamics making use of liberation point orbits. Along with this trend is the rise of small satellites ("small sats") and fractionated spacecraft in general. Compared to traditional monolithic spacecraft, small sats can often have higher maneuverability, be a fraction of the cost, and be more expendable in nature. The growing interest in these two areas drives the need for improvements in the area of relative motion in deep space. One obvious use of small sats in deep space is for …

Bond Behavior Of Magnesium Potassium Phosphate Cement (Mkpc) Coating For Steel Reinforcement, Eric Williams

Masters Theses

"This research investigates the bond behavior of magnesium potassium phosphate cement (MKPC) coated mild steel deformed bars in conventional concrete and concrete repair materials. For typical steel reinforcement in concrete, a thin “passive layer” develops around the reinforcement, which protects the reinforcement from corrosion. The concrete carbonates over time, reducing the protection of the passive layer and allowing chlorides, which corrode the reinforcement, to penetrate at an increasing rate. In some cases, to combat this corrosion, a protective layer is added to the reinforcement prior to installation. Common protective layers include epoxy coatings or zinc galvanization. MKPC is a novel …

Transfection Of Ionizable Lipid Nanoparticles On Raw 264.7 And Mda-Mb-231, Lavanya Bhargava

Masters Theses

"This thesis investigates the preparation, characterization, and transfection efficiency of various ionizable lipid nanoparticles (LNPs) formulated for the delivery of mRNA encoding enhanced green fluorescent protein (EGFP) in RAW 264.7 macrophages and MDA-MB-231 breast cancer cell lines. The ionizable cationic lipid studied are ALC-035, C12-200, C14-4, PPZ-A10, DLin-MC3-DMA. The study addresses the need for effective gene delivery systems to provide a safe and versatile platform that protects and transports nucleic acids into target cells. LNPs were synthesized using microfluidic mixing methods, incorporating lipid components such as the cationic lipids, DSPE, DOPE, cholesterol and PEG lipids to achieve controlled particle sizes, …

Lidar From The Skies: A Uav-Based Approach For Efficient Object Detection And Tracking, Baya Cherif

Masters Theses

"Recently, there has been a growing interest in deploying the Light Detection and Ranging (LiDAR) technology to gain traction in the autonomous vehicle industry, its applications are expanding into areas like smart cities, agriculture, and renewable energy. This work proposes an advanced approach to enhance aerial traffic monitoring using Li- DAR. We aim to provide accurate, real-time object detection and tracking from an aerial perspective by integrating Unmanned Aerial Vehicle (UAV) with LiDAR, culminating in a smart UAV-integrated LiDAR (A-LiD) sensor for traffic surveillance. We introduce an adapted version of one of the newest methods of the cutting-edge 3D object …

Fetal Acidosis Prediction Using Attention Enhanced Convolutional Neural Networks, Anusha Adhikari

Masters Theses

This study explores the integration of spectral mixtures of fetal heart rate (FHR) and uterine contraction (UC) signals to enhance the prediction of fetal acidosis, utilizing the CTU-CHB dataset. Several classification models were trained using two distinct oversampling techniques and inputs, demonstrating that models incorporating spectral mixtures significantly outperform those using raw signals. These models, particularly when combined with convolutional neural networks (CNNs) and attention mechanisms, achieved a notable F1-score of 0.98, with the highest model achieving an area under the Receiver Operating Characteristic (ROC) curve of 0.95. The research employs a variety of techniques including short-time Fourier transform and …

Characterization Of The Microstructural Changes Of Zrb2 Under Heavy Ion Irradiation For Molten Salt Reactor Applications, Narrie Loftus

Masters Theses

A primary challenge in finding suitable materials for Molten Salt Reactors (MSRs) lies in identifying those that concurrently exhibit high corrosion resistance, stability at elevated temperatures, resistance to radiation, and chemical compatibility with molten salts. 11B-enriched zirconium diboride (ZrB₂) is a potential candidate for applications in MSRs due to its unique combination of properties, including high melting point, high thermal conductivity, and resistance to corrosion in harsh environments. This ultra-high temperature ceramic (UHTC) has exhibited stability under extreme conditions, making it an attractive material for components within MSRs.

The microstructural response of ZrB₂ under heavy ion irradiation …

On Optimizing Sensor Data Collection, Processing, And Storage For Industrial Additive Manufacturing, Steven Thompson

Masters Theses

The widespread adoption of digital data management methods for transformative technologies, such as additive manufacturing (AM), within the aerospace industry is impeded by poor interoperability between AM component manufacturing processes. Moreover, data quality may be compromised due to sensor failures or other corruptions. Additionally, massive amounts of data are collected during these processes, often needing to remain accessible for decades. These storage costs can place a significant financial burden on smaller suppliers. This work aims to make digital data management methods more affordable and, therefore, approachable for smaller suppliers.

First, the design and initial implementation of an affordable and adaptable …

Auto-Tuning And Applications Of Transient Voltage Suppressor Models In Full-Wave Simulations, Daniel Peter Szanto

Masters Theses

System efficient electrostatic design (SEED) combines full-wave geometry information with SPICE models of non-linear protection devices, typically transient voltage suppression (TVS) diodes, to allow optimization and validation of electrostatic design (ESD) protection early in the design process. TVS models have previously been developed which may be used in SPICE simulation tools like Keysight ADS, but these models could not be used directly in full-wave simulation tools like CST Studio. A process was developed for converting existing ADS models of TVS devices to a form that can be used within a CST full wave/SPICE hybrid simulation. Three TVS models were converted …

Power Flow Control Of The Triple Active Bridge Converter, Lauryn Reece Morris

Masters Theses

With the rise of renewable energies, electric vehicles, and microgrids, the development of power electronic topologies that can seamlessly integrate these systems into the grid is crucial. The triple active bridge is an extension of the dual active bridge topology and is capable of energy storage or renewable energy integration into a power electronic converter and thus the power grid. Consisting of three H-Bridge converters, the triple active bridge topology is an expanding area of research to meet these growing demands. With the addition of the third bridge, the system has additional nonlinear characteristics which introduce complexity in solving for …

Overpressure Waveform Comparison Of High Explosive, Methane, And Coal Dust Explosions, Frank James Schott

Masters Theses

Methane and coal dust explosions remain a leading cause of catastrophic mining accidents, making it critical to understand their overpressure characteristics for better hazard modeling, mitigation, and regulation. Although high explosives (HE), flammable gases, and dusts have been studied separately, direct waveform comparisons in identical environments are rare. This study addresses that gap by comparing overpressure waveforms from HE, methane-air mixtures, and coal dust explosions to assess differences in peak pressure, impulse, rise time, and phase duration. Twenty-seven tests were conducted using standardized instrumentation and sensor arrays. Results showed that HE generated the highest peak pressures with short positive phases …

System Design For Highly Accurate And Efficient Target Detection In Triaxial Testing, Qingqing Fu

Masters Theses

Accurate and automated recognition of coded targets is crucial for high-precision photogrammetry-based measurements in triaxial testing. Traditional recognition methods, including those based on deep learning and table decoding, often struggle with issues such as perspective distortion, rotation, and variable lighting, leading to unreliable results. While deep learning approaches offer some improvements, they remain computationally intensive and sensitive to environmental factors.

This thesis introduces an innovative system that replaces deep learning algorithms with a blob analysis-based method for efficient and robust recognition of coded targets. The system also employs newly designed solid points of varying sizes and patterns, eliminating the need …

Ground Testing Of Cryogenic Environments In Vacuum Conditions, Lucas A. Scott

Masters Theses

The environment in the vacuum of space is unforgiving and ever-changing. Not only facing the lack of a protective atmosphere, but powerful radiation and extreme temperature ranges as well. Equipment destined for space must be hardened to withstand them. Just launching satellites that are theoretically able to survive these conditions is unfeasibly costly in the event of failure. Because of this, spacecraft must be tested in a simulated environment that can match the harsh climate in space. Therefore, it is the goal of the Gas and Plasma Dynamics Lab's (GPDL) to test and prove specific methods of recreating these conditions. …

Development Of Stalling Detection Algorithms And Operator Behavior Models For Evaluating Hydraulic Excavator Performance, Mateo Fernando Montenegro Defaz

Masters Theses

This study aims to develop a reliable algorithm for stalling detection and investigate how operator behaviors impact the truck-loading process, focusing on swing and bucket rotations. While the study of excavator digging conditions and equipment performance is well understood, describing stalling from telemetry data and the influence of operators’ behavior on overall system efficiency remain underexplored. This study seeks to: (i) develop a reliable algorithm for stall detection by analyzing key operational variables such as velocity and angles; (ii) implement statistical and machine learning techniques, specifically a Support Vector Machine (SVM) classification algorithm, to differentiate between ideal and non-ideal digging …

Long Short-Term Memory (Lstm) -Based Neural Network Model For Optimizing Composite Manufacturing Process Using Autoclave, Sourav P. Bolar

Masters Theses

The combination of high pressure and controlled heat plays a critical role in ensuring the uniform curing of composite materials, leading to parts with superior mechanical properties. In this study, three composite samples of IM7/CYCOM 5320-1, each cut into 12x12-inch squares, were placed in an autoclave at three different locations, spaced 6 inches apart. Sixteen thermocouples were randomly distributed across the setup to monitor the curing process as the autoclave temperature was systematically ramped up and down while maintaining constant pressure, creating a fully controlled curing environment. The primary objective was to optimize the curing locations to reduce machine runtime …

Frequency-Tracker And Power Supply For Piezoelectric Lunar Dust Removal Actuator, Praneeth Uddarraju

Masters Theses

"This work presents a reconfigurable phase-locked loop (PLL)-based control system for the resonant excitation of piezoelectric actuators aimed at automated removal of particulate contaminants from photovoltaic (PV) surfaces—particularly in extraterrestrial environments such as the lunar surface. Regolith or lunar dust buildup on solar panels is a serious hazard to the effectiveness of energy harvesting on extended missions. By using high-frequency structural excitation and inertial forces the suggested system removes surface impurities. Tunable Sallen-Key low-pass filters for reliable feedback conditioning are used in conjunction with a digitally implemented PLL on an FPGA (XLR8 platform) to precisely lock the drive frequency to …

Design Of A Spacecraft Power System Experiment, Jay Bakulkumar Kamdar

Masters Theses

This research delves into the design, implementation, and analysis of a controlled experimental framework for photovoltaic cell characterization and its application in spacecraft power systems. Such a system was simulated and validated by benchmarking characteristics of a photovoltaic module and implementing them in a system design simulation yielding performance data for comparative analysis. A hardware setup was developed to perform IV characterization tests under steady state thermal conditions. Experiments conducted across various thermal regulation profiles helped quantify the effects of temperature on the photovoltaic performance parameters. Active cooling reduced the steady state cell temperature by 17.9% and improved the cell …

Enabling Drone-Integrated Active Microwave Thermography Via A Slot Antenna Design, Alec P. Fitzmaurice

Masters Theses

Civil infrastructure inspection quality and inspector safety may be enhanced from the advancement in the capabilities of nondestructive testing and evaluation of remote or otherwise hard-to-reach areas such as nuclear power plants, wind turbines, bridges, or other civil infrastructure using drone-based Active Microwave Thermography (AMT). AMT is a nondestructive testing technique that utilizes high frequency energy (often radiated from an antenna) to induce heating in a specimen. Following this thermal excitation, an infrared camera is used to measure the resulting surface thermal profile. From this, defect indications may be detected. To enable drone-based deployment of AMT, where the antenna size …